#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
string find_first()
{
if (press("AB"))
{
if (press("A")) return "A";
else return "B";
}
else
{
if (press("X")) return "X";
else return "Y";
}
}
void add_next(string &cur, vector<string> &avail, int &now, int N)
{
if (cur.size() == N) return;
string ttry = cur + avail[0] + avail[0] + cur + avail[0] + avail[1] + cur + avail[1];
int out = press(ttry);
if (out - now == 2) cur += avail[0];
else if (out - now == 1) cur += avail[1];
else cur += avail[2];
now++;
add_next(cur, avail, now, N);
}
string guess_sequence(int N) {
vector<string> vv = {"A", "B", "X", "Y"};
vector<string> avail;
string first = find_first();
for (string ch : vv) if (ch != first) avail.push_back(ch);
string cur = "" + first;
int now = 0;
add_next(cur, avail, now, N);
return cur;
}
